This invention relates to a connector pair comprising two connectors mateable with each other and, in particular, relates to two contacts which are brought into contact with each other when the connectors are mated with each other.
For example, this type of contact is disclosed in JP-B 4302392 (Patent Document 1), the content of which is incorporated herein by reference.
As can be seen from FIG. 16, Patent Document 1 discloses a male terminal (contact) which is inserted into a female terminal (contact) to be brought into contact with the female terminal when two connectors (not shown) are mated with each other. The female terminal has a projecting contact portion while the male terminal has a contact portion extending in a plane. The contact portion of the female terminal slides on the contact portion of the male terminal upon the mating of the connectors. Each of the contact portions is plated with tin or the like. In other words, each of the contact portions has a plating layer. The plating layer of the male terminal has Vickers hardness larger than Vickers hardness of the plating layer of the female terminal so as to lower an insertion force upon insertion of the male terminal into the female terminal.
From a point of view of making contact resistance of the contact portion lower, the contact portion is preferred to be plated with silver or silver alloy. In other words, the contact portion is preferred to have a soft silver plating layer or a hard silver plating layer formed on base metal thereof. However, although the soft silver plating layer has low contact resistance, the soft silver plating layer is so soft to be easily abraded by sliding between the contact portions. When the plating layer is abraded, the base metal is exposed to raise the contact resistance. Moreover, the hard silver plating layer tends to have lowered conductivity because of contained hardening agent and tends to have reduced contact area because of its hard surface. As a result, the hard silver plating layer tends to have relatively high contact resistance. Accordingly, a silver or silver alloy plating layer, which has low contact resistance and is hardly abraded, is required.